The Present Disclosure relates to a board-to-board connector.
In order to electrically connect a pair of parallel circuit boards to each other, board-to-board connectors have traditionally been used, such as that disclosed in Japanese Utility Model Application No. 7-36375. Such a board-to-board connector connects a pair of circuit boards arranged in parallel to each other.
FIG. 12 illustrates another type of board-to-board connector. In FIG. 12, a male connector 801 is attached to a first circuit board 891, and a female connector 901 is attached to a second circuit board 991. The male connector 801 is provided with a male insulating housing 811 and a plurality of pin terminals 851 arranged in parallel to each other so as to pass through the male insulating housing 811. The distal ends of the pin terminals 851 are configured to protrude frontward from the distal end of the male insulating housing 811. The rear ends of the pin terminals 851 are configured to protrude rearward from the male insulating housing 811 and be bent downward to form male connection legs 852 which are configured to protrude downward. Each of the male connection legs 852 is inserted into each of a plurality of first through-holes 893 formed in the first circuit board 891 and is fixedly secured to be connected to a corresponding one of conductive traces of the first circuit board 891 by means of solders 892. In this way, the male connector 801 is mounted on the first circuit board 891.
The female connector 901 is provided with a female insulating housing 911 and a plurality of socket terminals 951 which is arranged in parallel to each other so as to be fitted in the female insulating housing 911. The rear ends of the socket terminals 951 are configured to protrude downward from the female insulating housing 911 to form female connection legs 952. Each of the female connection legs 952 is inserted into each of a plurality of second through-holes 993 formed in the second circuit board 991 and is fixedly secured to be connected to a corresponding one of conductive traces of the second circuit board 991 by means of solders 992. In this way, the female connector 901 is mounted on the second circuit board 991.
When the first circuit board 891 and the second circuit board 991 are connected together, the male connector 801 mounted on the first circuit board 891 is engaged by fitting with the female connector 901 mounted on the second circuit board 991. In this way, the respective pin terminals 851 are brought into contact with the corresponding socket terminals 951, and therefore, the first circuit board 891 is electrically connected to the second circuit board 991. Even when the male connector 801 and the female connector 901 are misaligned with each other, namely, displaced from each other, the displacement can be absorbed, so that the contact state between the pin terminals 851 and the corresponding socket terminals 951 and the engagement state between the male connector 801 and the female connector 901 can be maintained.
However, in the above-described board-to-board connector, the lower ends of the male connection legs 852 are configured to protrude from the rear surface of the first circuit board 891, and the lower ends of the female connection legs 952 are configured to protrude from the rear surface of the second circuit board 991. For this reason, a sufficient insulating distance might not be ensured between neighboring male connection legs 852 and neighboring female connection legs 952, respectively, and there might be a risk of short-circuit accidents.
Generally, in order to achieve electrical isolation without coating or covering neighboring conductive members with insulating materials, it is necessary to secure a sufficient insulating distance between the conductive members, namely, to secure a sufficiently long insulating distance. The insulating distance includes a clearance which is the shortest distance passing the space between two conductive members, and a creepage distance which is the shortest distance along the surface of the insulating materials between the two conductive members.
However, in the above-described conventional board-to-board connector, since nothing exists between the lower ends of neighboring male connection legs 852 protruding from the rear surface of the first circuit board 891 and between the lower ends of neighboring female connection legs 952 protruding from the rear surface of the second circuit board 991, the clearance and the creepage distance are short, and accordingly, there might be a risk of occurrence of short-circuit accidents.
When either one of the male or female connection legs 852, 952 are configured as terminals for connection to a power supply line, and both the first circuit board 891 and the second circuit board 991 are attached to a casing of an electronic apparatus, the insulating distance between the male connection legs 852 and the female connection legs 952 is short, and accordingly, there might be a risk of occurrence of short-circuit accidents.
In many cases, the casings of electronic apparatuses are generally formed of metals or composite materials of metals and resin and function as a ground line. In such cases, when a casing of an electronic apparatus exists at the rear side of the first circuit board 891 and the second circuit board 991, the insulating distance between the casing of the electronic apparatus and the lower ends of the male connection legs 852 protruding from the rear surface of the first circuit board 891 and the lower ends of the female connection legs 952 protruding from the rear surface of the second circuit board 991 becomes short, and accordingly, there might be a risk of occurrence of short-circuit accidents.